There is a technology that, in generation of a clock signal to be used for reproduction of audio data, a difference between an interval of a clock signal of a transmission apparatus and an interval of an acquisition time of clock information for synchronization is calculated. In the technology, a clock signal to be used for reproduction of audio data is generated at a frequency of a clock based on a value obtained by dividing the calculated difference by the interval of the synchronization clock information.
On the other hand, it is performed to acquire a packet transmitted through a communication line that couples terminals to each other and evaluate the quality of the communication line. Further, the quality of a communication line is degraded by an influence of an instantaneous jitter. Further, the instantaneous jitter may be calculated using a frequency of a clock signal used for transmission and reception of a packet (hereinafter referred to as “clock frequency”). It is to be noted that the quality of a communication line in the present specification signifies time-dependent stability of communication through the communication line. As a related art, there is Japanese Laid-open Patent Publication No. 2007-158543.